Hydraulic valve



T all whom it may concern.

Patented May 5, 1925 3 TnUnn ansson, or woncns'rnn, massaonns i'rrs.

HYDRAULIC VALVE. Q

Application filed March 10, 1923. Serial No. 62 .,202.

Be it known that I, rronn LAnssoN, a citizen of the United States of America, re-

' sidingat \Vorcester, inthe county of Worcester and Stateof Massacl iusetts, have invented certain new and usefulImprovements in Hydraulic Valves, of which the following is a full, eleaiyand exact specification.

My invention relates, to hydraulic valves and moreparticularly to'a three way piston valve mechanism for controlling the operation of a fluid motor.

One common type or mecl'ianism for operating the plungerofan elevator comprises,

. as shown in the patent to Reynolds, 314,720,

March 31, 1885,11 "three wayvalve which serves to control the admission of fluid under pressure to the plunge-r cylinder and its discharge therefrom. This'valve moved to predetermined positions by a piston contained in the valve casing, to which motive fluid is admitted by an auxiliary pilot valve 1 under the control of the operator.

In such prior constructions, movement of the valve is caused by the pressure of the incoming water supply, balanced pistons being employed to neutralize the back pressure of the fluid in the plunger cylinder. The speed of movement of the valvean'd hence the rate at which fluid flows into thecylinder is regulated by an adjustable screw or valve which throttles down the sizeioft-he water passage, and such rate is fixed in accordance with the preliminaryadjustments made upon the mechanism. The weight of the plunger is nearly balanced by counterweights so that the water pressure is required merely to do the work of lifting the unbalanced portion of the load and moving it at the. required speed. In operation, it is found that when the supply of water under pressure is suddenly shut off from the plunger cylinder, the plungertends to keep on moving because of the inertia of the heavy mass. Consequently the plunger may leave the surfaceof the water momentarily and then fallback on it with a shock which causes discomfort to the passengers in the elevator car. Such sudden stoppage of the water flow also puts a severe strain on the valves and'casing, hence it is desirable that mechanism bexemployed which automatically stops the motor g 'adually and that it not be necessary to depend upon the skill of the operator for this purpose.

It is accordingly the prime object of my invention to providea valve mechanism which will so control the application of fluid pressure to a motor that the motor may be gradually stopped in its movement and shocks incident to. valve operation elimi pressure from the motor port.

ith these and further objects as will be apparent in the following disclosure, my invention resides in the con'ibinationof parts described in the following specification and set forth in the appended claims.

In accordance with my invention, I propose to operate amotor, such as a reciproca tory plunger mechanism, by means of a three way piston valve device in which the pressure of the inlet motive fluid on the piston sets is normally balanced and the back pressure thereon from the fluid in the motor is unbalanced, whereby the rate of valve movement may be governed by the inertia of the load. To this end I preferably employ differential pistons on opposite sides f the port to the motor and balanced pistons on opposite sides of the port through which the fluid under pressure enters and. so arrange these partsthat the fluid pressure in the motor port controls, the valve movement.

Referring particularly to the drawing, the figure is a vertical section showing some what diagrammatically one embodiment of my invention, as applied to the operation of a plunger elevator, although it will be clear that this invention is broadly applicable to various types of hydraulic motors and particularly to those machines which comprise a recip'rocatoryv piston or plunger. As there shown, the motor for moving an elevator car comprises a plunger 10 mounted to reciprocate in a cylinder 1.1 which is closed atits lower endand has a suitable stufling box '12 at the otherfend through which the piston slides. As is well known in the art, th weight of the plungerand llU Cir

quired to lift but the unbalanced excess ot the weight. Fluid under pressure to raise the plunger is admitted to the cylinder 11 through a pipe 1 1 which also serves as an exit for the fluid when the plunger descends.

As a simplified "form of a three way valve capable of admitting motive fluid to the cylinder and of permitting its exhaust therefrom, I may provide a casing 15 which has an inlet port 16 for fluid such as oil or water maintained. under a hydraulic head, an exit port 17 and a motor port 18 which communicate with pipe 14. The ports 16 and 18 are arranged out of alignment on the side of casing 15 so that a main valve 20 placed therebetween. may be employed to control the flow of water to the motor cylinder. This valve 20 is mounted for recipro cation within a sleeve 21 which is suitably fitted within the casing 15. In order that the pressure of the water in inlet port 16 may not move the main valve 20 I provide a piston 22 also sliding within the sleeve 21 which with the valve 20 forms a balanced piston set. The valve 20 itself serves as a piston and owing to the fact that the pistons 20 and 22 are located on opposite sides of the inlet. port, any pressure of the water therefrom will not move the balanced piston set in either direction.

These piston members are mounted centrally upon a rod 24: and fastened thereto by suitable means so that they may move in unison. The upper reduced end 25 ot the rod passes through the end wall 26 oi? the casing 15, and has a sliding tit therein through a stutiing box. This construction forms a piston chamber 27 between the piston 22 and the wall 26.

The rod 24- also extends downwardly below the piston valve 20 and carries on its lower end 2!) a further piston valve 30 adapted to control the exit oi? water through the port 1?. In order to provide a cylinder for the piston 30, the sleeve 21 is extended as a reduced portion 32 within which piston 30 has a sliding .tit. A shoulder 33 between the enlarged and reduced portions of the sleeve serves to limit the downward movement of the piston valve 20. Above this shoulder ports 34; are formed within the sleeve which open into an enlarged annular chamber 35 within the casing 15, which communicate with the port 18 and pipe 1 1 of the cylinder. Similarly, the space 35 communicates with the inside oi? the reduced sleeve 32 through ports 36 so that when the valve 30 is raised to its uppermost position water may flow downwardly through port 18 and ports 36 to the exit port 17.

As will be readily apparent, the ports and pistons are so located and arranged that piston 22 remains always above the inlet opening 16. The valve 20 may be located as shown in the drawing above the sleeve opening 31 and therefore prevent the passage of water from port 16 through the valve or it may be lowered to the limiting position defined by shoulder 33 to permit water to flow to the cylinder. \Vhen valve 20 is in the intermediate position illustrated, valve 30 similarly remains within th lower portion of the sleeve 32 below ports 36 and the two valves 20 and 30 thereby prevent water flowing in either direction through the pipe 14. By raising the valve 30 while valve 20 remains in a closed position water may be permitted to flow from the cylinder downwardly through the exit.

As a simplified iorm oi? motor mechanism for actuating the valves, I may cn'iploy the construction shown in the drawing, whereby fluid under pressure may be admitted to the valve actuating cylinder chamber 27 to overcome the pressure of the fluid in the motor chamber on piston 20 and thus cause the pressure of the incoming fluid against the piston 22 to move the valve downwardly. To this end I may provide a pilot valve comprising a valve stem 40 slidably mounted in asleeve 41 provided in an extension 412 of the casing 15. Three sets of passages are provided within this extension 42, one an inlet passage 43 communicating through a port ist with the interior of the casing sleeve between pistons 20 and 22. The second passage 45 communicates with the cylinder space 27 as illustrated; and the third pas-' sage 1-7 communicates through a pipe 18. shown in dotted lines, with the outlet port 17.

The stem 4:0 has a. reduced central portion oi such length and size relative to the hications oi the openings 51, and 533 within the sleeve which con'lmunicate respectively with the inlet port. the piston cylinder and the outlet port. that it may connect passage 45 with either passage 43 or i? but not both at the same time. The upper and lower ends 5 1 and ot the stem have a sliding tit within the sleeve and are of such dimensions that when the stem is in the central position shown in the drawing, no water can flow into or out of the cylinder space 2?. By moving the stem 10 downwardly communication is effected from the port 16 through passage 43, the concentric space surrounding the reduced stem 50 and passage 45, to the space 27 thereby admitting water under pressure to the upper side of the piston 22. Since the upward back pressure on valve 20 from the cylinder 11 is then less than the downward pressure on the upard side of this valve piston, the not result is a downward movement of the piston valve 20 and the admission of water to the cylinder 11. Upon moving the stem 410 in an opposite direction and connecting passage 45 with the passage 17 and outlet pipe 4C8, the inlet pressure on the piston set 20 loo lilli lliJ lLIU

liltl and 22 bein'gibalanced l the upward move ment of the stem 24 canbe caused only by the back pfressurewithin the cylinder 11.

- V In order toutilize" the' m'otor' back pres tends to move the pistoirvalve sets upwardly andthis 1s overcome-only when suit able pressure is" maintainedon the upper side of piston 22. \Vhen such downward pressure on p1ston22 is removed by connecting passage 45 Wltl'l' the'outletport and the pressure of the inlet water-n pistons-2O and'22 is balanced-,* then the upward pressure on the under side-f piston valve of the unbalancedpiston-valve set 20,- results in anupward-movement of the valves and a consequent closinmofthe inlet port or opening ofthe "port 36 to the exit 17.

It will therefore be seenthat itwater is flowing? from the entrance 16 into the cylinder '11 the operator cannot reverse 1 the pilot valve and stop the flow of water so suddenly as'to cause the plunger to leave the water in' its" cylinder. Any tendency for the plunger '-to1ave; the waterresults in a decreased pressure withinthecylinder which" either slows up movement" of the piston valve or is insufiicient to move the-piston valve 'at all; Hence thefi ow of incoming water cannot be stopped 'instantlv audits retardation rate' is controlled by the inertia of the moving plunger 10"and its load 13.

As. this rate O'filfiOVBlhBDb gradually de-] creases the" unbalanced weight of J the" load thus graduallyexertsmore and more' pres-s sure upon the valve piston 20" until finally the valve pistonQO is moved upwardly to close the valve completely;

Similarly the downward movement of the plunger cannot be stopped so quickly as to ca u so ashockbht is automatically con trolled by the ,mechan-isnr as ar 'anged; When the piston setsare in their' uppermost position and the 1am is moving'rapidly downwardly and thel water has free exit through port'17, any attempt on the part of the] operator" to" close the outlet valve by admitting" water to 5 the cylinder casing 27 results in producingback'pressure on the under side otvalve piston 20 which neutralizes either completely or partially the downward pressure on the upper side of va'lve22, thereby preventing rapid: downward movement of the valve sets and I too sudden a: closure oftlreexitt The valve sets will tl'ierefore stop; in tlreir downward m ove ment or move as slowly as required until the back pressure in *eyl'i'nder" 11 is decreased to a 'sufiiei'ent extent to permit the valve '30 to be closed. p V

1a order to control the device manually,

I -1nay employ linkage connections which are substantially the same as those shown in the prior patent to Reynolds. As illustrated. alever 56 which is adapted to be movedby the operator is pivotally mounted on a h1g5? projecting from the wall 26. A"

linkage connection between the stem l0 and the rod 25 is provided through alevcr pivotally connected at one end to the rod and at the other end to a link 59,\v hiclr is pivotally mounted on the upper end oili the stem 40. The levers 56 and 58 are connected byalink 60. p

[Itwill therefore be seen that with such a construction when lever 56 is moved down= wardlvby the operator the pivotalconnew tion (ilqb'etween lever 58 and rod 25 first s'crvesas a fulcrum whereby lllOVGll'lQllt-ill the link 60 causes the link 59 and thestem 40 to descenththus permitting water to How into the cylinder space 27. The outer end o't'the lever 5(iis held in its new position, hence the pivotal point 62 is 'ten'iporarily fixed. Consequently as soonas water he pins to llow and move the piston valve sets downwardly, the pivotal point Gl now descends and turns lever 58011 its new fulcrum 62, thus serving to lift the stem 40 and, thereby return it to a neutral position. As

a result, further downward movement of the valve sets is prevented. \Vhcn lever 56 1s rais eilto its uppermost position the reverse be closed and the outlet valve opened by the back pressure of the water in the hydraulic motor being operated. The membe-r serves both to balance the pressure of the inlet fluid on valve "ZO and as a piston in the valve operatingcylinder 27, whereby when fluid is admitted to cylinder 27 the inlet fluidpressure may close the outlet port'and open the inlet to the motor; Upon moving the pilot valve to release the pressure in the operating cylinder the back pressure on valve 20 from the motor moves the piston :22 in the reverse direction; hence the operatingcylinder-piston device 27-22 has a 'direct action only in one direction. The motor It might also be tion is equally, applicable to motors contaiuacre back back pressure is the sole motive power aet ing in the opposite direction to close the inlet and open the outlet ports. it, is clear that other arr: ugements oi the pistons and valves may be. emplo ,cd within the scope of the objects of my invention and the append ed claims. it being merelv essential that the parts he so arranged that the motor back pressure may close the inlet valve and open the outlet valve when permitted by lluid moven'ieut in the operating: cylinder 27. also is to be observed that in actual practice the haamcingr piston may he made 5 rhtlv larger than valve .Ztl to overcome trictiom but the expressions balanced pistons and the like as used in the ('lcscription and claims are to he interprt' tcd as 'tull v covering: such a constriictiou. 'lhc expression ditterential pistons is likewise to be construed broadly. tloreovcr, it s immaterial, within the. scope o'l my ii'lvrntiom whicn ot the two relatively movable members. constituting piston and cylinder is actually movable and that equivalent arrangements well known in this art may he anployed.

Having; thus described my invention. what I claim as new and desire to secure by Letters Patent is 1. In combination with a hydraulic motor, a three wa v valve comprising a casing liav inc an inlet port, an outlet port and a port. to the motor and a piston valve device so CtlllS Zl'll't'titl and arranged relative to said ports that the back pressure :trom the motor is the sole motive power to ettect closing movement of the inlet valve.

9. A hvdatulic valve tor a motor comprisinn a casing having: inlet, outlet and motor ports. a set. of piston valves therein controlling the llow of water to and from the motor and m ans to move the valves to connect the inlet with the motor porh said parts being constructed and arranged so that the hyd aulic pressure in said motor controls the rate of movement of the piston valves.

A hydraulic 'alve comprising a casing; having inlet outlet and motor ports, a device to control the How of water through said motor port having" ditlicrcntial piston valves so arranged between the motor port and the other ports that. the hydraulic, pressure in the motor port? automatically regulates the rate ot the valve movement, and means including a. pilot valve to move said device to open the connection l'rom the. inlet to the motor port.

t. A hydraulic valve for a motor coinprising; a casing having; inlet, outlet and motor ports and means including; a sea ot piston 'alves therein controlling the ilow oit 'wator to and from the motor whereby the inlet fluid pressure is utilized to move the pistons against the motor pressure tor closing the outlet valve and opening the inlet valve and the motor back pressure is used to close the inlet and openthe outlet valves at :1 ate depending upon. the bacl: pressure in the motor.

5. A. lryd 'aulic valve comprising a casino; having inlet, outlet and motor ports, a pis-- ton valve controlling the [low ot water from the inlet to the motor port a piston connected with said 'alve and ai"an; ;ed to balance the inlet pressure thereon and a valve between the motor and outlet ports, said ports being Soarrangcd that. the motor bad; pressure the solo motive power to close the inlet port and open the outlet. port.

(3. A hydraulic valve tor a motor coinprising a casino; having; inlet, outlet and motor ports. pistons balanced against the inlet pressure and forming an inlet valve, an outlet valve cooperating; with said pistons, said parts being so arranged that? the motor back pressure may close the inlet valve and open the outlet valvtu and means to (71301] the inlet *alvc against such bacl; nessure. I

'4'. A hydraulic valve comprising a casing having an inlet. port, an outlet port and a motor port and a piston valve device hav- 'lDQ balanced pistons on opposite sides of the inlet port and unbalanced pistons between the motor port and the other ports, whereby the hydraulic pressure in the motor port may control the rate of movementof said device.

3. In combination with a hydraulic motor, a valve mechanism therc'tor comprisin; a casing having; inlet, outlet and motor ports, a balanced piston valve set receiving; the tluid pressure from the inlet port and a di'tl'erential piston valve set; receiving; the back pressure of the. fluid from the motor, a "alve common to said sets controlling the flow of fluid from theinlet to the motor port, said parts leiirc constructed ant arranged to prevent too sudden changes in the rate of fluid n'iovcnient.

9. A hydraulic valve con'iprising a valve casing having inlet, outlet and motor ports, a main valve controlling; the flow 0t fluid under pressure from the inlet to the motor port, a second valve controlling the. exit, ot :tluid from the motor port and means combined therewith operable by direct tluid lnessurc. to open the main valve and to permil back pressure from the motor to close said main. *alve and to open the outlet v: lvc.

10. A hydraulic valve comp 'isinc; a. casino having: inlet, outlet. and motor ports, a 'alvo piston between the inlet and motor ports a valve piston between the motor and outlet ports and a piston connected with said valve pistons operable by fluid pressure to open the valve between the inlet and motor ports, said piston and inlet alve piston being;- in balanced relation and the valve pistons being constructed and arranged relative to the valve is opened by the piston and closed by the back pressure in the motor port at a rate'controlled by pressure in said motor port. v

12. A hydraulic valve comprising a casing closed at one end and having inlet, outlet and motor ports spaced longitudinally thereof, a piston valve between the inlet and motor ports, a piston ad aCent said. closed end and constructed to balance said valve against the inlet pressure, means including a relatively movable piston and cylinder forming an outlet valve and cooperating with said piston valve to cause a difi'erential pressure to be exerted thereon from the motor port which tends to close the inlet port, and meansincluding a pilot valve-arranged to admit'fluid pressure to. the casing to move said piston and open the inlet port.

13. A hydraulic valve comprising a cylinder casing having inlet, motor and outlet ports, a main piston valve betweenthe inlet and motor ports adapted to limit the flow of water t'herebetween, a piston valve of smaller effective area between the motor and outlet portsto control the outflow of water, a piston connected to said valves, arranged to balance the pressure of the inflowing water onthe main valve and means including' a pilot valve eli'ect ve to unbalance said piston and valve and cause the main valve to open at a rate controlled by the back pressure of'the Water in said motor port.

14:. A hydraulic valve comprising a cylindrical vcasing having inlet, outlet and motor ports spaced longitudinally of the casing, a piston valve between the inlet and motor ports, a piston connected to said valve and arranged to balance the same against the inlet pressure means including a member adjacent the outlet port which cooperates with said piston valve to form a differential piston set, whereby the motor back pressure tends to move the same and close the inlet port, and means including an operating piston cylinder and a pilot valve to move the piston against the motor pressure and open the inlet and close the outlet valves. a

15 A hydraulic valve comprising a cylindrical casing having inlet and motor ports opening therefrom and a reduced end portion provided with an outlet port, a

main piston valve between said inlet and motor ports, a piston on theopposite side of the inlet port to balance said valve, an outlet valve of smaller effective areathan said main valve located between the motor port and the outlet port, means connecting said piston and valves for simultaneous sliding movement, and means including a pilot valve to move said piston'and open the inlet valve and to permit it to close under the back pressure inthemotor port.

16. A hydraulic valve comprising a casing which is closed at one end and hasat the opposite end an open reduced portion forming an outlet port, said casing being provided with an inlet port atone side and a motor-port between the inlet and out let ports; a piston between the inlet and the closed end or the casing, a piston valve between the inlet and motor ports which has the same ell'ective area as said piston and, is normally balanced thereby,a smaller piston valve between the motor and outlet ports connected to said main piston valve and forming anunbalanced piston set controlled by the fluid pressure in the motor port and a pilot \"tIlVQ arranged to introduce fluid under pressure between said piston andthe closed end of the casing.

Signed at Vorcester, Massachusetts, this fifth day of March 1923; A

VTHURE LARSSON, 

